As a direction-converting device for a radio-controlled running toy and the like, there is known a device in which a steering plate mounted on front wheels is turned to the left or the right through a worm gear mechanism by reversible operation of a servo motor for converting the direction of the front wheels to the straight, the right or the left.
In the direction-converting device thus constructed, however, frequent changes in the direction of the running toy may require frequent reverting operations of the servo motor, thereby generating sparks at various contacts forming an electrical system of the servo motor. Such sparks in the servo motor may cause damage to the electrical system of the servo motor and erroneous operation of the wireless controller. In particular, the servo motor is undesirably expensive in spite of its excellent control performance and greater expense is required for designing a control circuit to avoid the sparks.
In view of the foregoing, the applicant has already devised a direction-converting device which comprises an electromagnet energizable to a different polarity in accordance with a given instruction and a controlling element swingably supported at a predetermined distance apart from the electromagnet and provided at its swingable end with a pair of magnets of different polarities corresponding to the electromagnet but without contact therewith, said controlling element being engaged with a steering plate at its swingably shifting portion to shift the controlling element to the desired direction through attractive or repulsive relation to each magnet provided at the controlling element, depending on the energized state of the electromagnet, so that it may be of small size, superior in efficiency and very low in manufacturing cost, and accordingly obtained Japanese Pat. No. 1330571 (the Japanese Patent Publication No. 60-52827) directed thereto.
With regard to the direction-converting device operating through attraction or repulsion between the electromagnet and the magnets as described hereinbefore, however, in a small-sized running toy, the shift quality of the steering plate is small and the shift load thereof is also small, so that a whole device may be of small size with excellent efficiency, thereby reducing the manufacturing cost. In a comparatively large-sized running toy, on the other hand, the shift quality of the steering plate is larger and the shift load thereof is also larger. Then, the hereinbefore-described direction-converting device, when used, requires larger electromagnet and magnets, resulting in an increase in weight as well as in consumption of electric power for power-up. Furthermore, the use of attractive or repulsive relation between an electromagnet and magnets leads to a speedy shift of the steering plate simultaneously when the electromagnet is energized, resulting in disadvantages such as the impossibility of smooth steering control in a high speed running.